Convertible coupler



FIG. 1 is a perspective view of a convertible coupler, showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is an elevational view of one side thereof;

FIG. 4 is an elevational view of one end thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is an elevational view of the other side thereof;

FIG. 7 is an elevational view of the other end thereof; and,

FIG. 8 is a sectional view thereof taken along line 8--8 of FIG. 2. 

The ornamental design for a convertible coupler, as shown and described. 